1. Field of the Invention
The present invention relates to a catalyst for a reformer of a fuel cell system, to a reformer for a fuel cell system including the catalyst, and to a fuel cell system including the reformer. More particularly, the present invention relates to a catalyst that can effectively induce a reforming oxidation reaction in a reformer of a fuel cell system.
2. Description of the Related Art
A fuel cell is an electrochemical energy conversion device which changes chemical energy into electrical energy through an electrochemical redox reaction of an oxidant and a fuel such as hydrogen and a hydrocarbon-based material including methanol, ethanol, natural gas, and the like.
The fuel cell is a clean energy source that can replace fossil fuels. It includes a fuel cell stack composed of unit cells layered and combined in series and/or parallel and produces various ranges of power output. Since it has four to ten times higher energy density than a small lithium battery, it has been highlighted as a small portable power source.
Representative exemplary fuel cells include a polymer electrolyte membrane fuel cell (PEMFC) and a direct oxidation fuel cell (DOFC).
The direct oxidation fuel cell includes a direct methanol fuel cell that uses methanol as a fuel.
The polymer electrolyte fuel cell has advantages such as high power output density and energy conversion efficiency, operability at room temperature, and can be down-sized and tightly sealed. Therefore, it can be applied to a wide array of fields such as non-polluting automobiles, household electricity generation systems, and portable power sources for mobile communication equipment, military equipment, and the like.
A fuel cell system is composed of a fuel cell stack, a reformer, a fuel tank, and a fuel pump.
The fuel cell stack constitutes a body of a fuel cell, and the fuel pump supplies a fuel in the fuel tank to the reformer.
The reformer reforms the fuel to generate hydrogen gases, and supplies the hydrogen gases to the fuel cell stack.
In general, the reformer of a fuel cell system includes a reforming reaction part and a carbon monoxide reduction part. The reforming reaction part generates hydrogen gas from the fuel through a reforming catalyst reaction by thermal energy. The carbon monoxide reduction part reduces a concentration of carbon monoxide included in the hydrogen gases through an oxidation reaction of the hydrogen gas and oxygen.
The reforming reaction is performed by the reforming catalyst and therefore many researches have been made to increase activity of reforming catalysts.
The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore, it should be understood that the above information may contain information that does not form the prior art that is already known in this country to a person or ordinary skill in the art.